• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.388-390
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• 2003

Recent trend of sensor-less control of induction motor applied for commuter trains in Japan is introduced. Although many inverter-fed Induction motor driven trains have been produced so far, most of them were slip frequency based conventional V/f control system using shaft encoder. There arises a new trend to apply speed sensor-less vector control., for this inverter-fed induction motor drive system. The purpose of sensor-less control is to save, cost and improve system reliability. Several sensor-less systems now under testing on the actual railway company. This paper describes the survey of the fundamental structure and feature of representative sensor-less systems mentioned above.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.510-515
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• 2012

Feed drive systems are used to position the machine tool components carrying the cutting tool and workpiece to the desired location. Hence, their positioning accuracy and speed determine the quality and productivity of machine tools. In this paper, technical trend of machine tools feed drive systems are analyzed by patent mapping. And this paper suggested future development direction of feed drive systems. The analysis is carried out by using problem solution map (PSM) for the applied patent during January 2000 and December 2009 in Korea, Japan, EU and U.S.A.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.632-634
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• 2001

Recently, almost cruise are manufactured with electric propulsion system. The characteristics and types of the electric propulsion motors, which is one of the most important component in electric propulsion system for ships, are examined and compared. And a trend on the recent technical development of electric propulsion motors for ships is introduced.

• The Journal of Information Technology
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• v.12 no.4
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• pp.19-24
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• 2009

Recently, for the efforts of low-carbon deduction and to solve the problems of global warming, many industrial nations in world have been strengthening positively their competitive power into the research, development and industrialization of new renewable sources of energy and clean energy. In the most promising source of photovoltaic, it is essential that the government take an initiative role to develop and industrialize the materials, ingot or wafer, solar cell, power conditioning system and photovoltaic system, and need to establish both short-term and long-term technical development of goal setting and forward plan in the direction of the technical development strategy and forward industrialization for the strengthening of world market. This paper analyze new technology, policies and the market trend of photovoltaic field which are currently strategically and actively enhancing the research, development and practical-industralization by Korea and other nations.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.3
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• pp.266-270
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• 2013

Automatic tool changer(ATC) is typically provided to a machine tool to improve the efficiency of the machine tool significantly by saving time in moving, switching, installing and storing tools as well as adjusting a calibrating the machine tool. In this study, technical trend of machine tools automatic tool changer are analyzed by patent mapping. And future development direction of automatic tool changer has suggested. The analysis is carried out by using problem solution map for the applied patent during 2000 and 2010 in USA, Japan, Europe and Korea.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.593-597
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• 2002

The power conversion system for Fuel Cell Electric Vehicle(FCEV), technical trend, and a various type of Fuel Cell and its characteristics are presented. Especially, this paper is focused on the control methods of power conversion devices applied for the Fuel Cell Electric Vehicle, configuration of power system and operation mode of the bidirectional DC/DC converter. The prevalent topology for the power conversion systems, simulation results and development a tendency of FCEV and it's market investigations are introduced.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.998-1001
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• 2003

Recent trend of sensor-less control of induction motor applied for commuter trains in Japan is introduced. Although many inverter-fed induction motor driven trains have been produced so far, most of them were slip frequency based conventional V/f control system using shaft encoder. There arises a new trend to apply speed sensor-less vector control., for this inverter-fed induction motor drive system. The purpose of sensor-less control is to save, cost and improve system reliability. Several sensor-less systems now under testing on the actual railway company. This paper describes the survey of the fundamental structure and feature of representative sensor-less systems mentioned above.

• Journal of the Korean institute of surface engineering
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• v.45 no.1
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• pp.43-52
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• 2012

Recently, it has been developed for Eco-environment, Super light, Multi-functional nano materials. As needed mobile parts in Smart phone or TV, computer, information communication for high pass signal, multi-function, Magnetic thin film materials have been developed. As last, magnetic powder, sintered and sputtering parts were thick and low purity than electroplating layer, low pass signal and noise were resulted, vibrated TV screen. Because chemical complex temperature was high and ununiform surface layer, it has been very difficult for data pass in High Frequency (GHz) area. Large capacity data pass is used to GHz. Above GHz, signal pass velocity is dependent on Skin Effect of surface layer. If surface layer is thick or ununiform, attachment is poor, low pass signal and cross talk, noise are produced and leaked. It has been reported technical trend of Electrochemically plating and Surface treatment of Metal, Polymer, Ceramic etc. by dispersion/complex for Multi functional nano-magnetic material in this paper.

• 한국디지털정책학회:학술대회논문집
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• 2003.12a
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• pp.75-89
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• 2003

In this paper, we first summarize key components of integrated services of telecommunication and broadcasting. Definitions and typology of th e integrated services are organized th rough comprehensive analysis of recent convergence trend of telecommunications and broadcasting. Various issues on regulations, society cultures, and technical aspects of the convergence are identified. Next, we deal with the digital media broadcasting service which is one of the technical culmination of the telecommunication and broadcasting merged services. The focus of the analysis has been made on policy implications and comparative details with other similar services in the same category. Finally, we suggest the perspectives on forthcoming digital media broadcasting service developments, and implications to cope with this emerging technological breakthrough.

• Convergence Security Journal
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• v.15 no.7
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• pp.3-8
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• 2015

According to the advent of the seriousness of industrial technology outflow, concerns are mounting about the importance of security, recently. In this paper, I studied a research trend about industrial technology security and real condition of the outflow, analyzed it in various ways, and showed a seriousness of the issue and urgency of the security. Finally, I suggested methods of improving needed in the industrial technology security in legal, business and technical ways.